Need Help with My ECU!

[Alex7747]

okay guys i need some advice on my ecu..

First off, my ecu is not seeing power. The check engine light is not turning one when i put the key in the on position. Also, when i try to turn the engine over, i am not getting spark and i have not verified if my injectors are pulsing (how do i perform this). I do have fuel pressure however.

I cut my wire harness in half to reroute my fuse box and dam i regret that . But i hooked all the wires back to where they are supposed to go..except for like 7-8 wires that were all black so i assumed they were only grounds and i grounded them...i believe this is where i messed it all up.

My starter is wired to the cigarette lighter and can be cranked over without the key. and i rewired the fuel pump to a switch and can also be turned on without the key.

Since this car is my daily driver until i get another car in jaunary, i need it running soon. what i was thinking of doing is making a switch to manually turn on the ecu (doesn't matter if the key needs to be in there or not. to be honest id like to make my car turn on without the use of a key)....

Can i do this? if i make a switch to the power on the ecu (anyone know what pin(s) it is?) instead of using the ignition. I've been reading that i need to ground some of the pins to turn on the starter and fuel pump but they are already hooked up to switches. I just want to know if its possible, and if so can someone help me make it happen?

This will only be a temporary fix until i can find a wire harness for the car. But that won't be for a couple months.
-thanks for any help i may get.

 

[Anubis_4_99]

If i were you i wouldn't force the issue of getting power until you know for a fact all those wires were grounds. If they weren't and you force getting power, you could possibly damage something.

There is no way you should have cut the harness in half without labeling each and every wire at minimum, you really should have had a wiring diagram or something when you jumped into that.

It may be best for you to track down a replacement harness since its a daily driver, and work on repairing the tucked harness in your spare time.

 

[92AWDHX40]

Sounds like the fusebox relocation was the culprit, maybe easier to get another harness, i hacked mine once mistake second time got it right. Those wires go somewhere perhaps grounds problem could very well lie with no grounds hooked up, indicating no power to the ecu, or other isseus.

 

[Alex7747]

I did label all the wires. the thing is, i cut the fuse box harness. i never even touched the actually engine harness. And I'm tracing the black wires back now.

 

[92AWDHX40]

Grounds i had problems with those. pita.

 

[Alex7747]

Sounds like the fusebox relocation was the culprit, maybe easier to get another harness, i hacked mine once mistake second time got it right. Those wires go somewhere perhaps grounds problem could very well lie with no grounds hooked up, indicating no power to the ecu, or other isseus.

I believe so as well. Damn i hating wiring

 

[Alex7747]

If all the wires turn out to be grounds, could i make a switch for the ecu?

 

[92AWDHX40]

Not sure sounds complicated to me, im no wire wiz i learned my lessons maybe someone will chime in for you.

 

[Alex7747]

Not sure sounds complicated to me, im no wire wiz i learned my lessons maybe someone will chime in for you.

, thanks for the help either way. Time for me to get back into the garage!

 

[Alex7747]

okay so as of now I'm sourcing out a replacement wire harness, but for the mean time can someone help me out on making a switch to give power to the ecu? which pins need to get power and which need to be grounded?
thanks

 

[steve]

Until you fix your harness telling you how to power up the ECU will just be loading the bullets into the gun for you. There is something seriously wrong right now and until you fix it you will likely cause more damage.

 

[Alex7747]

okay, so i just bought another wire harness. and if the harness is good, it should fix my problems right?

 

[steve]

Assuming you don't have any problems installing it and you haven't damaged anything else.

 

[Alex7747]

Thanks for the help, ill update when i have the harness in the car

 

[andyb2637]

Was the car gettin any sort of power when you turned the ignition? Bells, dash lights, dome lights, ect ect.?? I just want to ask the obvious if none of that happened, your battery has power still left in it right?? Simple enough to make you crazy .

 

[Alex7747]

yes my battery had power...i was turning the engine over with the starter. I also used my moms battery and it was fully recharged...if only it was that simple

 

[jpdsm92]

do you have a pocket logger? whats your coolant temp reading? Sounds to me like you might have blown the ground on the ecu.

 

[andyb2637]

Lol sometimes it's those simple things that you look over. I'd second the blown/rotted ground to the ecu sounds like your trouble area...

 

[Alex7747]

i dont have a pocket logger . Also i replaced the wire harness and the car will wont start. im about ready to sell this thing. any help??

 

[steve]

It's hard to help without any details.
Do you have the wiring diagrams and an multimeter?

 

[Alex7747]

i have both but i dont know how to read the wiring diagrams ha. The only harness i messed with was the one for the fuse box under the hood, and i replaced the whole harness and im having the same problems.

 

[steve]

It's the details about the specific problems that are critical to helping you.
Now's a great time to learn how to read the diagrams. There's even a couple of pages in the manual that tell you how.

Then go to the power distribution system diagram and start checking for power starting at the battery and working from there. The fuse box is first place the power goes.

 

[josh1095]

off topic, impressive engine bay dude. good job.
as for ecu, u should be able to find out where switched power and everything comes in at on a factory manual or even a chilton/haynes manual, correct?